1. Field of the Invention
The present invention relates to an apparatus and a method for transmitting and receiving a broadcast signal and a data structure thereof.
2. Discussion of the Related Art
A digital broadcasting system can transmit not only broadcasting data originally transmitted by an analog broadcasting system, but also additional information such as text, images, etc. However, the amount of data transmitted is limited by the particular bandwidth of the digital broadcasting system. Further, the broadcasting system transmits images or data in predetermined time intervals and the images are sequentially received in the same time intervals. The images are also displayed in the same order as they are received.
In more detail, FIG. 1 is a timing diagram illustrating how images are sequentially transmitted, received and displayed according to a predetermined time interval. In FIG. 1, “n” denotes a time interval in which an image is transmitted and received. The horizontal line also corresponds to a time axis and each vertical line corresponds to a point in time in which each image is transmitted and received. As shown in FIG. 1, images A, B, C, D, E and F are sequentially transmitted every “n” time interval.
Further, as shown in the bottom of FIG. 1, the images A-F are sequentially received and displayed in the same order. However, there is a slight time delay between when the images are transmitted and displayed (see in particular the time delay of image F).
Accordingly, when images are transmitted in a narrow band, the images are displayed in the receiver very slowly, because the speed at which the broadcast objects are displayed can not be equal to a speed at which the broadcast objects are transmitted. Further, as shown in FIG. 1, the images are displayed in the same order that they were transmitted. That is, the receiver does not have any control over how the images are displayed. Rather, the way the images are displayed is strictly controlled by the transmitter.
Therefore, three-dimensional images or other types of video contents can not be normally displayed normally due to a limited bandwidth of the broadcasting system.